To recognize possible issues, web developers should display the performance of the HAR file; files are extremely useful when problems can not be repeated by the developer.
Using web development software, anyone can create a HAR file and submit the file for review to the developer.
The Drought format HTTP Archive (HAR), published on August 14, 2012, gives the following definition:
This specification defines an HTTP transaction archive format that can be used by a web browser to export detailed performance data about web pages that are loaded.
Since then, the document has been abandoned, however several modern browsers, like Google Chrome, Mozilla Firefox, Internet Explorer, and software including Fiddler, help HAR.
The HAR file extension is .har. Any web browser, specialized viewer apps built for .har files, any JSON viewer software or extension and any text editor will access the files.
The object of HAR files is when the browser connects to a site to establish an activity record. The file contains information about the loaded tools, cookies, content downloaded, and several specifics of the link.
How to create HAR files
In general, the network tools of the developer tools of the browser used must be opened, the affected site must be loaded (or part of it, depending on the problem) and a save option must be used to save the documented data as a HAR file.
Create HAR files in Google Chrome
- Open the Developer Tools by using the keyboard shortcut Ctrl-Shift-I, or go to Menu> More Tools> Developer Tools.
- Go to the Network tab.
- Load webpage, if the web page is already open the refresh page.
- Now look toolbar to Activate the down arrow icon, this will show Export HAR when you hover the mouse over it. This way you can save the HAR file on the local system.
Follow the same method on most Chromium-based web browsers like Brave, Opera, Vivaldi, or Microsoft Edge.
Create HAR files in Mozilla Firefox
- To open the Network tab in Firefox use Ctrl-Shift-E shortcut key, or use Menu> Web Developer> Network.
- Load webpage, if the web page is already open the refresh page
- Now click on the settings icon. this icon is situated on the developer tools bar. After this select Save all as HAR to export the data.
How to view HAR files
In most browsers that support their development, HAR files can be loaded. In these browsers, you can find options for importing HAR files from the network, and you can use the imported data to examine potential site issues.
There are some other tools to see HAR files like the online HAR file viewer.